Chemically synthesized sugar esters for the control of soft-bodied arthropods

Abstract

The invention relates to an improved process for the synthesis and application of sugar esters, that are useful as effective, environmentally-safe pesticides for the control of soft-bodied arthropod pests.

What is claimed is:  
     
       1. A nonaqueous method for synthesizing low molecular weight aliphatic sugar esters comprising: 
       (a) dissolving a sugar in an aprotic polar organic solvent to form a first sugar solution,  
       (b) dissolving an aliphatic acid chloride in a suitable solvent to form a first chloride solution,  
       (c) adding pyridine to said first sugar solution to form a second sugar solution,  
       (d) mixing said first chloride solution dropwise to said second sugar solution to cause an esterification reaction and form an esterification reaction solution,  
       (e) adding a sodium bicarbonate solution after said esterification reaction to decompose any pyridine hydrochloride byproducts to form a product solution,  
       (f) recovering sugar esters from said product solution.  
     
     
       2. The method of  claim 1  wherein the aliphatic acid chloride is the chloride of an acid selected from the group consisting of caproic acid, caprylic acid, 3-methylvaleric acid, 4-methylvaleric acid, hexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic acid, heptanoic acid, 5-methylheptanoic acid, octanoic acid, nonanoic acid, capric acid, decanoic acid, dodecanoic acid, and lauric acid. 
     
     
       3. The method of  claim 1  wherein said aprotic polar organic solvent is selected from the group consisting of dimethylformamide, dimethylsulfoxide, and pyridine. 
     
     
       4. The method of  claim 1  wherein said suitable solvent for the aliphatic acid chloride is selected from the group consisting of acetonitrile and acetone. 
     
     
       5. The method of  claim 1  wherein the molar ratio of sugar to acid chloride is 1:2.5. 
     
     
       6. The method of  claim 1  wherein said esterification reaction is maintained at a temperature of approximately about 60 to 65° C. 
     
     
       7. The method of  claim 1  wherein said recovery step includes 
       (a) filtering the product solution to form a filtrate,  
       (b) evaporating said filtrate to dryness, and  
       (c) dissolving the dry filtrate in a solvent selected from the group consisting of acetone and chloroform.  
     
     
       8. The method of  claim 7  wherein said filtrate is dissolved in a solvent selected from the group consisting of acetone, methanol and mixtures thereof, to form a solution having a concentration of approximately about 1% to 5% weight/volume. 
     
     
       9. The method of  claim 8  wherein said solution is stirred into water to form a sprayable aqueous solution having a concentration of approximately about 0.050% to 0.25% weight/volume. 
     
     
       10. The method of  claim 7  wherein said filtrate is dissolved in chloroform to form a chloroform solution. 
     
     
       11. The method of  claim 10  further comprising the steps of 
       applying said chloroform solution to a chromatographic column,  
       collecting fractions,  
       drying said fractions and redissolving them in acetone,  
       identifying the sugar ester in each fraction, and  
       preparing a pesticide composition of each separate fraction by diluting the acetone solution with water to form a sprayable aqueous solution having a concentration of approximately about 0.050% to 0.25%.  
     
     
       12. A pesticide composition effective for treating plants infested with arthropod pests comprising an effective amount of a mixture of sugar esters produced by the method of  claim 1 . 
     
     
       13. A pesticide composition effective for treating plants infested with arthropod pests comprising an effective amount of a mixture of sugar esters produced by the method of  claim 9 . 
     
     
       14. A method for treating plants infested with arthropod pests comprising administering a pesticidally effective amount of the composition of  claim 12  to pest infested plants. 
     
     
       15. A method for treating plants infested with arthropod pests comprising administering a pesticidally effective amount of the composition of  claim 13  to pest infested plants.